get_month_categoryRetrieve the monthly budget for a specific YNAB category by passing the month and category ID, so you can review planned spending and available funds.
Get category budget for a specific month
| Name | Required | Description | Default |
|---|---|---|---|
| month | Yes | YYYY-MM-DD, first of month | |
| budgetId | No | ||
| categoryId | Yes | Category ID |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v6.1.0Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"Input schema / properties / budgetId / descriptionRemoved value: -"Budget ID (uses default if not provided)"Input schema / properties / month / descriptionPrevious value: -"Month in YYYY-MM-DD format (first of month)"New value: +"YYYY-MM-DD, first of month"Output schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"v5.4.0Output schema / properties / result / descriptionRemoved value: -"Structured result returned by Get Month Category."v5.2.0v5.1.1v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so safety is covered. The description adds only the month-scoping idea, restating what the schema already implies, and says nothing about what the returned "budget" figure represents.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single short sentence with no filler and the scope stated up front. Its brevity is efficient, though it borders on under-specification rather than tightness.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
An output schema exists so return values needn't be explained, but the description leaves the undocumented budgetId parameter, the ambiguous semantics of "budget," and the sibling differentiation unaddressed — gaps an agent would hit when calling.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 67%: month and categoryId are documented but budgetId is bare. The description does not mention budgetId at all, nor does it clarify the required YYYY-MM-DD month format or the relationship between budgetId and the other parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a verb and a resource ("Get category budget") plus a scope ("for a specific month"), which is better than a tautology. However, "category budget" is ambiguous — it is unclear whether this returns the budgeted amount only, or budget vs. activity vs. balance — and the description does nothing to distinguish it from siblings like get_category or get_month.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance on when to use this over get_category, get_month, or get_overspent_categories. The agent must infer the choice from names alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.